This is a so-called "Staßfurter Topf" (Staßfurt pot). It is the successor to the first version of this fixture, which was initially produced in Leipzig.
In 1978, production of this simple fixture was moved from Leipzig to Staßfurt, and the design was simplified even further, unfortunately making it worse and more primitive.
The most striking feature of this second version is the black bakelite shade, which replaced the aluminium sheet reflector. The inside of the reflector was not painted white.
The fixture is uncompensated, i.e. without a capacitor, and another mechanical drawback is that only one screw instead of two screws was provided for attachment to a boom.
Another disadvantage is the ‘pairing’ of the two materials, cast aluminium and simple steel screws. In older fixtures, this screw connection is heavily corroded and almost impossible to loosen.
The screws sometimes break off during disassembly and then have to be laboriously drilled out.
The photo shows a fixture for use with a NARVA NF 125W mercury vapour lamp, dismantled into its individual parts. It has never been used and is therefore in mint condition.
The ballast is held in place with a very simple sheet metal bracket, which is attached to the bakelite reflector with screws. Some damage occurred during transport of new lights, and the screws broke out of the bakelite.
So, that's enough text for now. Here is a photo of the dismantled fixture:
